1. Field of the Invention
The present invention relates-to a control mechanism for controlling an axial movement of a driving shaft of a machine such as a drilling machine. The control mechanism comprises a clutch means cooperated with a sleeve member which is operated by two pivotal handles such that when pivoting the handles the driving shaft is lowered and is stopped when returning the handles.
2. Brief Description of the Prior Art
Conventional drilling machines for example, which has a driving shaft driven by a motor, a drill bit or a suitable knife member is fixedly connected to the driving shaft so as to machine a workpiece. A movement of the driving shaft is generally controlled by two ways, one of which comprises at least two limit switches disposed to an inner periphery defining a passage through which the driving shaft rotatably extends so as to cut off the motor to set an uppermost and a lowermost position of the driving shaft. The other way comprises an electronic control means which utilizes circuits and electronic members to send signals to relative parts of the machine so as to achieve purposes of controlling the movement of the driving shaft. However, both of the two ways cannot avoid inertia force of the driving shaft even if the motor is stop. This situation makes the driving shaft further move beyond a desired position so that the workpiece could be damaged. In addition, the electronic members has a limited life term so that the whole mechanism could run out of control if a main or important member suddenly does not work as desired.
The present invention provides an improved control mechanism for controlling a driving shaft to mitigate the problems as mentioned above.